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BMW/VW "Fast" Charging E/W Coast

Discussion in 'Charging Standards and Infrastructure' started by Ciaopec, Sep 26, 2016.

  1. Ciaopec

    Ciaopec Member

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    BMW and Volkswagen Take on Tesla Motors With a New U.S. Fast-Charging Network -- The Motley Fool

    Click bait, perhaps. These statements alway infuriate me:

    How fast are these "fast-charging" stations?
    They're not quite up to the level of the latest versions of Tesla's vaunted Superchargers. Tesla claims the Superchargers can add "up to 170 EPA-rated miles of range in as little as 30 minutes." But the new Chargepoint stations aren't bad: Chargepoint's 50 kW stations can add up to 200 miles of range per hour, while the 24 kW stations can add up to 100 miles of range per hour.

    Why not cite all charge rates in the same format. It would appear that the Chargepoint stations are almost as fast when Tesla is listed in "30 min increment" and Chargepoint is listed in "hour" increments.
     
  2. Canuck

    Canuck Active Member

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    So Chargepoint added some more stations and that's BMW and VW's fast charging network? That's pretty pathetic.
     
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  3. CSFTN

    CSFTN Member

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    The best way to state the rate in the same unit is to in fact state the rate in the same unit! Not % change per unit of time, or even miles worth of electricity per unit of time but actual amount of electricity per unit of time. Superchargers are 140 kW per hour under ideal circumstances, CCS is currently 50kW per hour under ideal circumstances, and derated CCS is currently (usually) 24 kW under ideal circumstances. Just teach people that kW per hour is in fact the unit we should be using.
     
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  4. vinnie97

    vinnie97 Member

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    Isn't that BMW in a nutshell?
     
  5. Jeff N

    Jeff N Active Member

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    I assume you know this but just for clarity....

    No existing Tesla vehicle has been seen to draw more than about 117 kW even though the charger itself is good for 145 kW now. Perhaps the new 100 kWh cars will be able take a little more now.

    CCS itself today is already specified for 100 kW (200A at 500V peak) but almost all of the actual units installed today are limited to 50 kW (also known as 125A).

    I agree that DC chargers should always be rated with the peak amperage and voltage and peak kW they can output. However, it's perfectly sensible for specific car models to be rated in terms of the number of EPA range miles they can recharge in a certain period of time based on both their charge amperage and voltage, peak kW intake, as well as their EPA range efficiency.
     
  6. ggr

    ggr Roadster R80 537, SigS P85 29

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    I think your units are very confused. Power is measured in kW. Energy is measured in kWh. I think what you are trying to say is "How fast can I replenish the energy stored in my battery?" for which the answer would be kiloWwatt hours per hour... which is kW. In any case, kW per hour makes no real world sense.
     
  7. CSFTN

    CSFTN Member

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    #7 CSFTN, Sep 27, 2016
    Last edited: Sep 27, 2016
    Yeah, I get that. But, I'm trying demonstrate something accurate and simple, and differentiating between power and energy is a mile too far. That's why I specifically avoided those terms (at least, I think I did). I used the term "amount of electricity" as the other terms while being more precise are in relative terms unnecessarily erudite. At least for Joe average.

    Now, if there's member of the 'audience' who can't take my bastardization of the units of measurement, then ... I guess I would just explain it as miles of driving per hour of charging. At least then then units would be correct. I just hate letting people keep their often preconceived notion that charging an EV is a difficult task that takes at the very least several hours. Using the term "hours" IMO reinforces the concept that it takes hours not less than an hour (again, lots of details that can be fleshed out in that set of statements).
     
  8. ringi

    ringi Member

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    Given that a car can only use the full charging power when the cells are not overheating and they tend to overheat as their charge level builds up, a car that is able to take a 100kw charge at peak will be using the peak output of a 50kw charger for more of the charging time then the peak output of a 100kw charger.

    Therefore a 100kw charger does not charge in half the time of a 50kw charger.
     

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